Electrostatic atomizing device and humidifier using this

ABSTRACT

A carrier is used to carry a liquid, and a high voltage is applied between a discharge end of the carrier and an opposed electrode to emit ionized liquid particles. The carrier has a liquid collecting end opposite to the discharge end to feed the steam of the liquid from a steam generator, condensing the liquid therearound, and feeding the condensed liquid to the discharge end. Accordingly, even when the liquid contains cations such as those of Ca and Mg, the steam of the liquid can extremely reduce the content of these impurities, avoiding the precipitation of the impurities at the discharge end of the carrier to assure stable electrostatic atomization.

TECHNICAL FIELD

The present invention relates to an electrostatic atomizing device foremitting a liquid in the form of tiny ionized particles and a humidifierusing the same.

BACKGROUND ART

Japanese Patent Publication No. 3260150 discloses a priorelectrostatically atomizing device. The atomizing device utilizescapillary structure as a liquid carrier to feed the liquid to dischargeend of the carrier by a capillary effect. A high voltage is appliedbetween the carrier and a surrounding housing to emit the liquid asionized particles from the discharge end. When the device uses thewater, for example, city water, electrolytic water, PH adjusted water,mineral water, vitamin-C or amino-acid contained water, or watercontaining a deodorant such as fragrant oil or aromatic, minerals suchas Ca or Mg possibly contained in the water will advance to the distalend of the capillary structure and react with CO₂ in the air toprecipitate as CaCO3 or MgO, hindering the electrostatic atomization.Therefore, it has been a problem to require maintenance of removing theprecipitants regularly.

DISCLOSURE OF THE INVENTION

The present invention has been achieved to overcome the above problemand to present an electrostatically atomizing device and the humidifierusing the same which can avoid the precipitation of impurities containedin the liquid at the discharge end of the carrier for maintaining stableelectrostatic atomization over a long period of use.

The electrostatically atomizing device of the present invention includesa carrier having a liquid collecting end and a discharge end opposite ofthe liquid collecting end, the liquid collecting end collecting a liquidfor feeding the liquid to the discharge end. The device includes a firstelectrode, a second electrode, and a voltage source. The voltage sourceapplies a voltage across the first and second electrodes to charge theliquid at the discharge end, thereby emitting the liquid in the form oftiny ionized particles. The characterizing feature of the presentinvention is to include a steam supply which feeds a steam to the liquidcollecting end of the carrier for condensation of the liquid therearoundin order that the condensed liquid is fed to the discharge end of thecarrier. Thus, even with the use of the liquid in which cation of Ca orMg is dissolved, the content of Ca or Mg cation can be minimized by theeffect of steam, thereby inhibiting the impurities from being fed to thedischarge end of the carrier and avoiding the lowering of theelectrostatic atomization by the precipitation of the impurities.Accordingly, frequent cleaning of the discharge end can be avoided tokeep the stable electrostatic atomization over a long period of use.

Preferably, the case accommodating the carrier has its interiorseparated by a partition into a condensation compartment and adischarging compartment. The carrier extends through the partition todispose the liquid collecting end within the condensation compartment,and the discharge end within the discharge compartment. The condensationcompartment is communicated with the steam supply to be fed the steamtherefrom to give the steam condensed liquid to the liquid collectingend. Thus, the condensation compartment serves as a condensation spaceto feed the condensed liquid effectively to the liquid collecting end.

The condensation compartment is preferably configured to make a circularflow of the steam around the liquid collecting end of the carrier. Thecircular flow increases the chance of contact between the steam and thecarrier to improve condensation effect by cooling of the steam, assuringto feed the liquid stably to the discharge end of the carrier.

The condensation compartment may be provided with a liquid absorber forcondensing the steam thereat and feeding the condensed liquid to theliquid collecting end of the carrier.

Further, the electrostatically atomizing device is preferred to includea fan producing a forced air flow, and an air duct introducing theforced air flow into between the discharge end and the second electrode.With this arrangement, the tiny ionized particles of the liquidgenerated between the discharge end and the second electrode is carriedon the forced air flow to spread over a wide range. In this case, abaffle may be provided to shield the carrier from the forced air flow,avoiding undue evaporation of the liquid from the carrier.

Thus configured electrostatically atomizing device is preferablyincorporated into an appliance such as a humidifier. The humidifier hasa fan generating an forced air flow and a steam path for directing aportion of the steam from the steam supply as being carried on theforced air flow and emitting the steam outwardly. Consequently, inaddition to general humidification effect by the steam, the tiny ionizedparticles of the liquid can be dispersed to improve skin beauty effectdue to high skin penetration capability that the tiny ionized particlesexhibit, as well as room deodorizing effect.

These and still other objects and advantageous features will becomeapparent from the detailed explanation of the preferred embodiment whentaken in conjunction with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a vertical section of an electrostatically atomizing device inaccordance with an embodiment of the present invention;

FIG. 2 is a perspective view of an atomizing unit in the above device;

FIG. 3 is a side view of the atomizing unit;

FIG. 4 is a perspective view of a humidifier incorporating the atomizingunit;

FIG. 5 is a top view of the humidifier;

FIG. 6 is a cross-section taken along line 6-6 of FIG. 5;

FIG. 7 is a cross-section taken along line 7-7 of FIG. 5; and

FIG. 8 is a cross-section illustrating a modification of the atomizingunit.

BEST MODE FOR CARRYING OUT THE INVENTION

An electrostatically atomizing device in accordance with one embodimentof the present invention is configured to ionize particulate water, forexample, so as to generate ionized water particles of a nanometer size,and include an atomizing unit M for electrostatically atomizing theliquid, and a steam generator S providing a steam of water. As shown inFIG. 1, the atomizing unit M includes a case 30 accommodating aplurality of capillary carriers 20. The case 30, which is made of afirst tube 31 and a second tube 32 coupled to each other, has itsinterior space divided by a partition 10 into a condensation compartment33 and a discharge compartment 34. The capillary carrier 20 extendsthrough the partition 10 as being held thereby to define a liquidcollecting end 22 at its portion projecting into the condensationcompartment 33, while defining a discharge end 21 at its pointed end ofa portion projecting into the discharge compartment 34. Extending fromthe first tube 31 surrounding the condensation compartment 33 is a duct35 for introducing the steam from the steam generator S, therebycollecting the condensed water at the liquid collecting end of eachcapillary carrier 20. The condensed water is absorbed in the liquidcollected end 22, and is accumulated in an absorber 24 which is mountedaround the liquid collected end 22 and act to feed the condensed wateralso to the capillary carriers 20.

A stud 36 projects from the inner bottom of the first tube 31. Aplurality of axles 38 extends from the stud 36 to support the liquidcollecting ends of the capillary carriers 20. The axles 38 and thecapillary carriers 20 are located centrally within the condensationcompartment 33 to define an annular space around these parts. Thus, thesteam supplied into the condensation compartment 33 is caused to give acircular flow as indicted by arrows in FIG. 1, prompting the coolingeffect to enhance the condensation of water, and therefore supplying thewater constantly to the liquid collecting ends of the capillary carriers20.

The partition 10 is embedded with a first electrode 11 which isconnected to the capillary carriers 20 to charge the water being carriedthrough the carriers 20. The first electrode 11 has a terminal 12 forconnection with an external high voltage source 70. The second tube 32surrounding the second compartment 34 has a front opening within which asecond electrode 40 disposed. A high voltage generated at the highvoltage source 70 is applied across the first and second electrodes 11and 40. The high voltage is applied continuously or in the form of apulse across the electrode plate 40 and the partition 10.

Each of the capillary carriers 20 is made of a porous ceramic and shapedinto a porous bar having a diameter of about 5 mm and a length of about70mm in order to feed the water collected at the liquid collecting end22 to the discharge end 21 by the capillary effect.

The high voltage source 70 is configured to apply the high voltagehaving an electric field strength of 500 V/mm, for example, between thefirst electrode 11 and the second electrode 40, developing anelectrostatic atomization between the discharge end 21 at the distal endof the capillary carrier 20 and the second electrode 40 opposed to thedischarge end such that tiny ionized water particles are emitted fromthe discharge end 21 towards the second electrode 40. That is, the highvoltage induces Rayleigh disintegration of the water being emitted fromthe discharge end, thereby generating negatively-charged water particlesand emitting the mist of the tiny ionized water particles.

The second electrode 40 is molded from an electrically conductive resinand shaped into a circular electrode plate having a plurality ofopenings. Each opening has its periphery disposed in a closely opposedrelation to the discharge end 21 to make the discharge between theperiphery and the discharge end 21. The second electrode is formed onits periphery with a terminal 42 for connection with the high voltagesource 70. The second tube 32 is fitted with a cover 37 which is made ofa dielectric material and is formed with discharge ports 39 incorrespondence with the openings of the second electrode 40, as see inFIGS. 2 and 3.

Each of the capillary carriers 20 is made of the porous ceramic materialof particle size of 2 to 500 μm and has a porosity of 10 to 70% to feedthe water to the discharge end 21 by the capillary effect using minutepaths in the ceramic. The ceramic is selected from one or anycombination of alumina, titania, zirconia, silica, and magnesia, and isselected to have a PH at the isoelectric point lower than PH of thewater in use. The basis of such selection is related to mineralcomponents such as Mg and Ca possibly contained in the water beingutilized. The mineral components contained in the water are refrainedfrom advancing to the discharge end of the capillary carrier 20 andtherefore refrained from reacting with CO₂ in the air to precipitate asMgO or CaCO₃ which would otherwise impede the electrostatic atomizationeffect. That is, the electroosmotic flow in the capillary carriers 20can be best utilized so that Mg or Ca ions dispersed in the water isprevented from advancing to the discharge end 21.

The partition 10 supports at its center an ionizing needle 60 which iselectrically charged to the same potential as the capillary carriers 20.The ionizing needle 60 has a pointed end projecting in the dischargecompartment 34 in alignment with the discharge ends 21 of the capillarycarriers 20. The capillary carriers 20 are evenly spaced in a circleconcentric to the ionizing needle 60. The ionizing needle 60 is opposedto a center opening of the second electrode 40 to cause a coronadischarge therebetween, thereby negatively charging molecules such asoxygen, oxide, or nitride in the air to generate negatively chargedions, while restraining the generation of ozone. Thus, by applying ofthe high voltage negative potential to the ionizing needle 60 and thecapillary carriers 20, the negatively charged ions are generated fromthe ionizing needle 60 concurrently with the atomization of the liquidat the discharge ends 21.

An air introduction chamber 50 is formed on one circumferential portionaround the second tube 32. The air introduction chamber 50 is connectedthrough an air duct 94 to a fan 90 in order to introduce a forced airflow generated at the fan 90 and direct the air flow in the dischargecompartment 34, whereby the resulting air flow goes from the dischargecompartment 34 through the discharge ports 39 of the cover 37. Theionized tiny water particles of negative charge generated between thedischarge end 21 and the second electrode 40 as well as the negativelycharged ions generated between the emitter needle 60 and the secondelectrode 40 are carried on the air flow to be spread in the form of amist into a wide space. A baffle 52 is disposed between the dischargecompartment 34 and the air introduction chamber 50 so as to protect thecapillary carriers 20 from being directly exposed to the forced air flowbeing introduced to the air introduction chamber 50, but to allow theforced air flow to be directed through an inlet 54 at the front end ofthe baffle 52 to between the discharge ends 21 of the capillary carriers20 and the second electrode 40.

FIGS. 4 to 7 illustrate one example in which the atomizing unit M isincorporated into the humidifier 100. The humidifier 100 includes ahousing 101 with a detachable tank 110, the housing 101 accommodatingtherein a steam generator S, a fan 90, and a high voltage source 70. Thesteam generator S is configured to heat the water being supplied fromthe water tank 110 to generate the steam, which is discharged through asteam discharge path 120 and out of a steam port 122 at the front of thehousing 101, as shown in FIGS. 6 and 7. The steam discharge path 120 hasits portion communicated with the duct 35 for supplying the steam to thecondensation compartment 33 of the atomizing unit M. The fan 90 iscommunicated through an air path 92 with the steam discharge path 120immediately upstream of the steam port 122, thereby giving off the steamout of the steam port 122 as being carried on the forced air flow fromthe fan 90. The air path 92 is also communicated with the air duct 94 ofthe atomizing unit M to direct the part of the forced air flow into thedischarge compartment 34 by way of the air introduction chamber 50,whereby the tiny ionized water particles and the negative ions generatedwithin the discharge compartment 34 are carried on the forced air flowto be emitted out of the discharge port 39 of the cover 37.

Although the illustrated embodiment is configured to supply the part ofthe steam from the steam generator S into the atomizing unit M whileemitting the rest of the steam out of the steam port 122, it may beconfigured to supply the entire steam into the atomizing unit M.

When the mist of the tiny ionized water particles caused by theelectrostatic atomization is generated at a rate of 0.02 ml/m within anelectric field strength of 500 V/mm or more with the use of thecapillary carrier 20 of which tip diameter is 0.5 mm or below, the mistcontains the very fine ionized particles having the nanometer particlesize of 3 to 100 nm, which react with the oxygen in the air to give theradicals such as hydroxyl radicals, superoxides, nitrogen monoxideradicals, and oxygen radicals. The mist of the tiny ionized waterparticles, when released into a room, can deodorize substances containedin the air or adhered to the walls. The following are reaction formulasbetween the radicals and various kinds of odor gases.2NH₃+6.OH→N₂+6H₂O   ammonia:CH₃CHO+6.OH+O₂→2CO₂+5H₂O   acetaldehyde:CH₃COOH+4.OH+O₂→2CO₂+4H₂O   acetic acid:CH₄+4.OH+O₂→CO₂+H₂O   methane gas:CO+2.OH→CO₂+4H₂O   carbon monoxide:2NO+4.OH→N₂+2O₂+2H₂O   nitrogen monoxide:HCHO+4.OH→CO₂+3H₂O   formaldehyde:

In addition, the tiny ionized water particles of nano-meter size canwell penetrate into keratinous membrane in human skin to improvemoisture retention of the skin.

FIG. 8 illustrates a modification of the above atomizing unit M which issimilar in structure to the above atomizing unit except for a concave 23formed in the liquid collecting end 22 of the capillary carrier 20. Thesimilar elements are designated by the same reference numerals. Theconcave 23 increases the contact area of the capillary carrier 20 withthe steam to obtain more amount of the condensed water, enhancing theefficiency of supplying the water to the capillary carriers 20.

Although the above embodiment is explained with reference to an examplein which the water is utilized to generate mist of the tiny ionizedwater particles, the present invention is not limited to the particularembodiment, and can be applicable to the use of the various liquidsother than the water. The available liquid includes the water containingvaluable components such as vitamin C, amino acids, a deodorant such asfragrant oil or aromatic, and includes a colloidal solution such as amake-up lotions.

1. An electrostatically atomizing device comprising: a capillary carrierhaving a liquid collecting end and a discharge end opposite of saidliquid collecting end, said liquid collecting end collecting a liquidfor feeding the liquid through said carrier to said discharge end, afirst electrode electrically charging said liquid, a second electrodeopposed to said discharge end, a voltage source applying a voltageacross said first and second electrodes to thereby electrostaticallycharge the liquid at said discharge end and emitting the said liquid inthe form of tiny ionized particles, a steam supply that provides a steamof said liquid and feeding said steam to said liquid collecting end ofsaid carrier for condensation of said liquid therearound in order thatthe condensed liquid is fed through said carrier to said discharge end.2. The device as set forth in claim 1, wherein said carrier is mountedwithin a case which is separated by a partition into a condensationcompartment and a discharging compartment, said carrier extendingthrough said partition to confine said liquid collecting end and saiddischarge end respectively within said condensation compartment and saiddischarging compartment, said condensation compartment communicatingwith said steam supply to be supplied with said steam.
 3. The device asset forth in claim 2, wherein said condensation compartment beingconfigured to make a circular flow of said steam around the liquidcollecting end of said carrier.
 4. The device as set forth in claim 2,wherein said condensation compartment is provided with a liquid absorberfor condensing said steam and feeding the condensed liquid to saidliquid collecting end of said carrier.
 5. The device as set forth inclaim 1, further including a fan producing a force air flow; and an airduct introducing said forced air flow into between said discharge endand said second electrode.
 6. The device as set forth in claim 5,further including a baffle shielding said carrier from said forced airflow.
 7. A humidifier including the electrostatically liquid mistingdevice as defined in claim 1, said humidifier including a housingprovided with a fan producing a forced air flow said housing includingan steam duct which receives a portion of said steam from said steamsupply to carry said steam on said forced air flow to direct the steamoutside of said housing.